Microscopic Theory of Magnon-Drag Thermoelectric Transport in Ferromagnetic Metals
arXiv:1209.0685 · doi:10.1143/JPSJ.81.113602
Abstract
A theoretical study of the magnon-drag Peltier and Seebeck effects in ferromagnetic metals is presented. A magnon heat current is described perturbatively from the microscopic viewpoint with respect to electron--magnon interactions and the electric field. Then, the magnon-drag Peltier coefficient $Π_\MAG$ is obtained as the ratio between the magnon heat current and the electric charge current. We show that $Π_\MAG=C_\MAG T^{5/2}$ at a low temperature ; that the coefficient $C_\MAG$ is proportional to the spin polarization of the electric conductivity; and that for $C_\MAG<0$, but for $C_\MAG>0$. From experimental results for magnon-drag Peltier effects, we estimate that the strength of the electron--magnon interaction is about 0.3 eV for permalloy.
3 pages, 2 figures, accepted for publication in Journal of the Physical Society of Japan